Air-pressure gauge



June 22,1926.

E. G. WEAVER AIR PRESSURE GAUGE Filed Dec. 22. 1924 INVENTOR m W W ATTORNEYS Patented-June 22,1926. 'n Y' 1,599,141.

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EDWARD G. WEAVER, OF BUTTE, MONTANA.

AIRPRESSURE GAUGE.

Application filed December 22', 1924. Serial No. 757,476.

This invention relates to a gauge `for the Referring more particularly to the draw-V" valves of air containers, and more particuings 1 designates an externally threaded hollarly to a valve stem used in connection with low barrel having its opposite ends interan automobile tire. nally threaded to receive at its inner end 5 An object-of the invention is the provision the threaded plug Q of one clamping me1n- 6c of a device which will indicate at all times ber 23 which cooperates with a. washer 4 for the pressure in a container or tire to which locking the barrel l to an inner tube when it is connected. the nut 5 engaging the external threads of Another object of the invention is the pro the barrel 1 is forced down tight upon the vision of a gauge forming part of the valve washer 4. 65

stem of an automobile tire valve through Barrel 1 has a portion of its wall cut away which the air is adapted to be forced for into forni an elongated sight'window 6. At a iiating the tire with the device functioning point opposite the sight window 6 is formed to constantly indicate the pressure of the a groove 7 on the inner wall of the barrel tire. 1. This groove provides a passage for fluid 10 A further object of the invention is the betweenfthe outer wall of an air-tight cylin provision of a gauge applicable to the valve der S and the barrel 1 and connects a cham-` stem of an automobile tire valve for indicat ber 9 at the outer end of the barrel with a ing constantly the pressure of the air in chamber l() located at the innerend of "said 2c the tire and in which the indicating instrubarrel. v

mentality includes a compensating means for A passage 1l in the plug 2 andclamping temperature changes wherebythe gauge will member 3 connects the chamber 10 with the properly register. interior of the inner tube of a tire.

This invention will be best understood The wall of the cylinder 8 iscut-away as from a consideration of the following deshown at 12 to receive a curved window 13, 80 tailed description, in View of the accompanythe curvature of which conforms to the are ing drawing forming a part of the speciiicaof a` circle, the radius of which is equal to tion; nevertheless it is to be understood that the radius of the inner wall of the cylinder the invention is not confined to the disclo- V8. The window lcloses the opening formsure, being susceptible of such changes and 4ing the sight window 6 inthe barrel land 85 modifications which shall define no material as will be seen in Figure 2 the member 18 departure from the salient features ofthe extends the full length of the cylinder 8. invention as expressed in the appended The window is sealed in any approved manclaiins. Y ner to prevent the passage of air.

a ln the drawings: o The inner end of the cylinder -8 is closed 90 Figure 1 is a view in elevation of the by a plug 14 having a boss lneatly itted complete assembly of the tire valve and within the lower end of the cylinder 8 with gauge. the lower end of said cylinder resting upon Figure 2 is a vertical section of the com a shoulder formed by the boss 15 and the in bined tire valve and gauge. main body of the plug 14. lThe body of the 95 Figure 3 is a horizontal section taken plug is of such a diameter that it will close along the line 3-3 of Figure 2. the lower end of the 'barrel y1 above the plug Figure 4 is `a horizontal section' taken 2 except for the passage 7. The upper end valong the line 4-4 of Figure Q. of the cylinder 8 is closed by a plug 16 hav- VFigure 5 1s a view of the indicating eleing a boss 17 fitted within the upper end of lfy ments of the gauge removed from their supthe cylinder 8, the diameter of the plug be port. n ing such that it closes the upper-'end of the Figure G is a vertical section of the U- barrel 1 and below the inner end of valve tube forming one of the elements of the cage 18. The plugs 14 and l close the opgauge. posite ends of the cylinder 8 thereby forming 105 Figure is a. vertical section of an elea substantially air tight chamber in said ment of the gauge which compensates'for barrel. The plugs 14 and 15 are pressed temperature changes and cooperates with into the barrel and form a tight fit to prethe U-tube in Figure 6 for determining the vent the passage of air therearound. indication at a definite pressure. A rubber cushion 19 seated on 4the inner 11.0

f or` external pressure.

Y the element 22.

end of the boss 17 cooperates With a rubber cushion 20 on the inner end of the boss l5 for maintaining the U-shaped gauge element 2l and the straight gauge element 22 in position and prevents breakage of the same. The cushion 2O is providedl with an opening to receive the lower endof the element 22 Which alines Withasoclret 23 inthe plug lfor receiving the lower end 24 of A horizontalpassage 25 formedthrough the vvall ofthe-barrel l and the plug 14's connects the pockety 23 and likewise the restrictedbore 26 `of the clement 22 with theratmosphere;`

The bore 26V of the element22 has a column of colored glycerine 27 therein which is normally colored blaclr for apurpose Ito be presently described;

The U-tube 2l as shown more-particularly invFigure 6 is provided with tivo legs 28 andf29, each-havinga ybore respectively designated; as BOand 8l and connected yat their/lower ends as shownat 32. The upper end of the leg. 28 is closed While the bore 3l` of the leg 29 is sealed by a bulb The bulb isniade of' flexible kmaterial which may be expandedor contractedby either vinternal The U-tube 2l is partially filled with a column of glycerine 34 colored red to distinguish it from the column 2T. The normallevelr of both liquids is indicated by aline-designated 4by the numeral The bulb vacts as a well and contains red-glycerinewvhich isin coinmunication with the columny of glycerine in leg 29.

The-valve cage 18 is providedwitli av central bore 36 inv Wihcliris mounted a valve stem 37. A spring 38 maintains ,the valve upon its seat; A threaded nipple 39 is ada-ptedto receive the', dust capor a union connected with the flexible conduit of an air tank, Y

The threaded I passa-ge 40 'isY formed in the plug 14' andr intdwhich is adapted to be screwed a threaded stud 4l which' Willpermit a restricted quantity of air to be admitted'to the air-tight cylinder 8 to insure a gradual and steady increase of' pressure Within'container 8 during inflation, thereby protecting thev bulb or Well 88 against sudden impact of air Which would other- Wise occur when a Vhose containing high pressure-is attachedy at the nipple The cushion 20 is also shown With an opening alining with the passage 40.

The operationof vmy device is as follows:

Air is applied through the nipple 39 into chamber 9" Whencetheair under pressure passes through the conduit 7 into chamber l0 through passage ll intoithe inner tube v(not shown). Since the cylinder 8 is airtight except for the restricted passage between the threaded studiil and the perforation 40 only a small quantityof the air Will be forced into said cylinder. Pressure on the bulb 33 Willvk force the column of red glycerine up inthe bore 30 of the leg 28 of the U-tube 3l and the top of said column Will? be located approximately at the line 85 in Figure 6 for a pressure of 50 pounds and' at a temperature. of 70 degrees. For the saine temperature the column 27 of black glycerine will also stand at the line designated by the numeral 35. n

lVhen the temperature changes or is raised the air inthe upper,y end'of theregistering element 22 Will force the column of glycerine 27 downwardly'and the expansion of the air in the boreBO dueto an increase of temperature Will also force the column- Sli downwardly. Nevertheless when the upper endsof the column.` are in the saine horizontal plane the registering device Will indicate the pressure ofv pounds as before.

The lower end ofthe tube22 is open to the atmosphere so that changes in thetemperature Will cause variation inthe position of the upper end of the column of glycerinein said tube. .y

lt must also be borne in mind. that the device can be sograduated in order to deter mine any other pressures Within a reason able limit for air in the inner, tube. .Furn therniore While lfy have describedthe device asopeiatingunder the pump it is toy be understood that the device will indicate` at all` times the pressure in the tire since the tire is in communication through passage ll with` the indicating device.

lVhat I claim-is:

An-` air pressure gauge comprising a barrel, a substantially air-tight container Withinthe barrel, a .U-'tube formedrof glass and having a restricted bore, one leg vofthe tube being open, a flexible bulb connected lWiththe open end and adapted toibe con-V tracted'by air pressure in the container, a column of liquid in the bore adapted to be elevatedin the closed leg of the tube to a predetern'iined point for a definite pressure in the container, the closed leg having, a column of airi above the column of liquid,

a second glass tube provided with abore and an indicating liquidin the bore, said second tube havingca column of air above the `column of liquid, the upper end ofthe column of liquid inthe closed legof theY U-tube registering Withk the upper end ofthe column of liquid inthe second tube at a. prede termined pressure in the bariel regardless of the temperature.

2. An air ,pressure gauge comprising a barrel, a substantially air-tight container Within the barrel, a.- U-'tube formed ofglass andhaving-a restricted bore, one leg of the tube beingopen, a flexible bulbrconnected with the open end and adapted tobe con-- tracted byair pressurein the container, a column of liquid in the bore adapted to be elevated in the closed leg of the tube to a predetermined point fora definite pressure in the container, the closed leg having a column of air above the column of liquid, a second glass tube provided with a bore and an indicating liquid in the bore, said second tube having a column of air above the column of liquid, the upper end of the column of liquid in the closed leg of the U-tube registering with the upper end of' the column of liquid in the second tube at a predetermined pressure in the barrel regardless of the temperature, the lower end of the container and the barrel being provided with communicating passages open to the atmosphere, said passages being in communication with the lower end of the second indicating tube to permit lowering of the column of liquid when the air in said tube expands due to a rise in temperature.

3. An air pressure gauge comprising a barrel, a substantially air-tight container within the barrel, a U-shaped tube having a restrictedbore, one leg of the tube being open, a dexible bulb connected with. the open end of the leg and adapted to be contracted by air pressure in the container, a liquid column in the bore adapted to be elevated in the closed leg when the bulb is contracted, said U-shaped tube being transparent, and means affected by variations in temperature and cooperating with the liquid column in the U-shaped tube for indicating the pressure in the barrel for a predetermined degree.

l. An air pressure gauge comprising a barrel, a substantially airtight container within the barrel, a U-shaped tube having a restricted bore, one leg of the tube being open, a flexible bulb connected with the open end of the leg and adapted to be contracted by air pressure in the container, a liquid column in the bore adapted to be elevated in the closed leg when the bulb is contracted, said U-shaped tube being transparent, and means affected by variations in tempera ture and cooperating with the liquid column in the U-shaped tube for indicating the pressure in the barrel for a predetermined degree, a window in the barrel for inspecting the position of the liquid column in the Ushaped tube, said container and barrel having a restricted communication therebe open,

tween to permit air under pressure vto enter the container. Y

5. An air pressure gauge comprising a barre-l, a substantially airtight container within the barrel, a U-shaped tube having a restricted bore, one leg of the tube being open, a flexible bulb connected with the open end of the leg and adapted to be con tracted by air pressure in the container` a liquid column in the bore adapted to be elevated in the. closed leg when the bulb is contracted, said U-shaped tube being transparent, and meansfaflected by variations in temperature and cooperating with the liquid column in the U-shaped tube for indicating the pressure in the barrel for a predetermined degree, said container being neatly fitted within the barrel to provide chambers at the opposite ends of the barrel, the inner wall of the barrel being provided with a groove running longitudinally thereof for placing the chambers in communication with each other, one of the chambers being adapted to be placed in communication with an external pressure.

6. An air pressure gauge comprising a barrel, a substantially air-tight container within the barrel, a U-shaped tube having a restricted bore, one leg of the tube being open end of theleg and adapted to be con* tracted by air pressure in the container, a liquid column in the bore adapted to be elevated in the closed leg when the bulb is contracted, said U-shape'd tube being transparent, a straight transparent tube provided with a restricted bore, the upper end of the bore being closed, the lower end being in communication with the atmosphere, a liquid column in the bore adapted to be affected by temperature changes where# by the column is elevated or lowered, the column of liquid in the closed .leg of the U-shaped tube being of such a length that its upper end will be normally in the same plane with-the upper end of the liquid column in the straight tube for a deinite pres sure in the barrel, said barrel and container being in restricted communication, said barrel adapted to be placed in communication with an external air pressure.

EDVARD G. WEAVER.

a flexible bulb connected with the4 

